Submersible motor for deep well turbine pumps



June 24, 1941.

VIII/A 'II/I; VIII/[I4 'lI/III/II/IIIIIIIIIJYIIIIIIIII/fl 'IIIIIIIIIIIII III/I4 II VIII/Ill A. NELSON 2,246,751

SUBMERSIBLE MOTOR FOR DEEP WELL TURBINE PUMPS Filed Jan. 16, 1940 I) a L a n l n 2,

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INVENTOI? Patented June 24, 1941 UNITED STATES PATENT OFFICE SUBMERSIBLE MOTOR FOR DEEP WELL TURBINE PUMPS 4 Claims.

One of the later developments in the installation of deep well pumps is the mounting of an electric motor on the bottom end of the drive shaft instead of the upper end as has heretofore been the practice.

In placing the driving motor at the bottom end of the shaft it is, of course, submerged in the water in the well, and consequently one of the many problems presented by this arrangement is that of maintaining proper lubrication of the working parts. This lubricationof the working parts of the motor and cooperating elements is accomplished by sealing the same within a casing substantially filled with lubricating oil. But here another problem is encountered, namely, that of preventing the forces developed by operation of the pump, including the high water pressures developed exterlorly of the casing, from replacing the oil in the casing with water from the well.

The above last named problem has not heretofore been satisfactorily solved, to my knowledge. Such means as has been used being either inefficient or costly or impractical for other reasons.

"It is, therefore, the object of my invention to provide a pump motor assembly constructed and arranged to effectually seal the lubricating fluid within the motor casing and prevent its replacement with water from the well regardless of the pressure that may be developed thereby.

It is also an object of my invention to provide an assembly of the character indicated that will be simple in form and construction, economical to manufacture, easily "assembled and maintained in satisfactory working condition, and highly efiicient in its practical application.

In the drawing:

Figure 1 is a longitudinal section through a well'casing with a motor assembly involving my invention positioned therein, one-half of said assembly being in section.

Figure 2 is a detail sectional view at A, Figure 1.

In the drawing I show at l a cylindrical motor case part closed at the bottom by means of a member 2 screwed into the bottom end at 3, and having a cap 4 threaded in to the top end at 5.

The cap 4 is secured to an adapter section 6, and through the medium of said section the motor case is suspended from, and is a unitary part of, the line of bowls and the discharge casing extending to the top of the well and not shown in the drawing.

The cap 4 has a central opening 1 formed therein, and mounted on said cap as at 8 an extending through said opening is a depending sleeve 9. The sleeve 9 is therefore, a nonrotating member extending axially of the motor case to a point adjacent its bottom end.

The drive shaft Ill, upon which the pump impellers are mounted, passes through the sleeve 9 without contact therewith and terminates in a squared end ll below the bottom end of the sleeve, the corners of the squared end being chamfered as at l2.

At 13 is shown a rotor sleeve encompassing the fixed sleeve 9 without contacting the same and having a bottom member threaded on to its lower end as at II, this member having a square hole l5 formed therein to receive the squared end of the shaft l0.

Inserted between the rotor sleeve l3 and the motor case I are upper and lower bearings I6 and H and the motor IS, the stator of the motor being spaced from the bearings by cylindrical spacers as l9 and 20, and the rotor of the motor being spaced in like manner by means of cylindrical spacers 2| and 22. In this arrangement the fixed parts are clamped between parts 2 and 4, while the rotating parts are clamped between l4 and a nut 23 threaded on to the top end of sleeve l3.

It will now be readily seen that when lubricating oil is introduced into the motor casing as at'24 all of the working parts are bathed in the oil which descends to the point 25 around the shaft 10, and sleeve l3.

Below the level 25 the part 2 is filled with water maintained at the same pressure as the water in the part 6 by a tube 26 connecting the two parts as shown.

As stated above, the sleeve 9 is spaced a little from the shaft l0, and since the water above and below is maintained at the same pressure it follows that this space is also filled with noncirculating water and a perfect seal is provided for the motor chamber 21. The lubricating oil will, of course, pass downwardly between the nonrotating sleeve 9 and the rotating sleeve l3 to level 25, but as long as the water level rises above the lower end of sleeve 9 the oil cannot escape, the pressure thereon being the same on both sides of sleeve 13.

In the present instance the squared shaft end connection II with the part ll effects a driving connection between the two and centrally supports the shaft. The passages 28 formed by chamfering the corners of the shaft portion passing through hole l5 permit maintaining the water at the same level within and without the sleeve it, but since the round portion of the shaft seats upon the part II it is slightly cut away at the chamfered corners as at 29 to prevent its closing ofl the said passages.

While the tube 26 is shown as conducting water to the bottom of the receptacle I, 2, 4, it is obvious that since the shaft and tube 8 are not in contact the water seal may be eflected by the water flowing downwardly therebetween, thereby rendering the tube 26 unnecessary.

The seal may also be eflected, though not as economically, by substituting mercury for the water to the level 25. For the purpose of this disclosure it may be assumedthat the head of lubricant in pipe 24 will be sumcient to balance any water pressure that may develop in the bottom of the receptacle.

Although but one specific embodiment of the invention has been illustrated and described herein, it will be understood that various alterations in the details of construction and mode of assembly and operation, may be made without departing from the scope of the invention as indicated in the appended claims.

I claim:

1. A submersible device comprising, a unitary and concentric closed motor caslngand open ended shaft tube, said tube projecting into the casing from the top and disposed to cooperate therewith to form a closed lubricant holding chamber, a pump shaft extending through the tube, a motor associated with the casing in said chamber and drivingly connected to the shaft below the bottom of the tube, there being open communication between the bottom 01' the tube and the lower end of the chamber.

2. A submersible device comprising, a closed unitary and concentric motor casing and open ended shaft tube, said tube projecting ink the casing from the top and disposed therewith to form. a closed lubricant holding chamber, a pump shaft extending through the tube, a sleeve encompassing the tube to a point adjacent the top or the chamber, a driving conand the lower end of the shaft,

nection between the sleeve and shaft below the bottom of the tube, and a motor associated with the casing in said chamber and drivingly connected to the sleeve, there being open communication between the bottom of the tube and the lower end of the chamber past the bottom of the sleeve.

3. A submersible device comprising, a fluid receptacle having an open ended tubular portion extending inwardly from its top to a point adjacent the bottom thereof to form the inner wall of a closed lubricant chamber, a shaft passing therethrough, a sleeve of greater diameter than the tube encompassing the same, and having open communication with the two ends of the receptacle, an electric motor disposed between the receptacle wall and sleeve to rotate said sleeve, 0. driving connection between the sleeve and a lubricant supply conduit leading to the lubricant chamber, the shaft having a lesser diameter than the tube whereby water may pass through the tube to the bottom of the receptacle when the device is submerged and close the bottom of the lubricant chamber above the bottom of the tube when the chamber is filled with lubricant.

4. A submersible device comprising, a fluid receptacle having an open ended tubular portion extending inwardly from its top to form the inner wall of a closed lubricant chamber, a shaft passing therethrough, a sleeve of greater diamto cooperate '19 eter than the tube encompassing the same, an electric motor disposed between the receptacle wall and sleeve to rotate said sleeve, a driving connection between the sleeve and the lower end of the shaft, means for introducing lubricant into the lubricant chamber, means for introducing water from the well in the bottom of the receptacle when the device is submerged, and means for equalizing the lubricant and water pressures to maintain the water level adjacent thebottomof the tube.

" ALBERT NELSON. 

